1. Field of the Invention
This invention relates to a hot-melt color ink-jet recording process making use of a color hot-melt ink. More particularly, it relates to a color ink-jet recording process that can form images with a superior color reproduction when images are recorded by heating a color hot-melt ink to melt at a temperature higher than normal temperature.
2. Description of the Related Art
As inks used in conventional ink-jet recording systems, water-based inks employing water as a main solvent and oil-based inks employing an organic solvent as a main solvent are commonly used. Printed images obtained using the water-based inks have a poor water resistance in general. On the other hand, the use of oil-based inks can provide printed images having a good water resistance.
However, these water-based inks and oil-based inks are liquid at room temperature, and hence feathering tends to occur because ink rapidly permeates when images are printed on recording paper, and that a sufficient print density has been achievable with difficulty. Also, because these inks are liquid at all times, they tend to cause formation of deposits such as aggregates of dyes from inks during their storage, and such deposits have caused a great lowering of the reliability of ink-jet recording systems because of, e.g., clogging of nozzles.
In order to overcome such disadvantages of the conventional inks of a solution type, what is called a hot-melt ink-jet recording system making use of inks which are solid at normal temperature and melt upon heating are proposed, and various hot-melt inks used in the ink-jet recording system of this type are proposed. Stated specifically, U.S. Pat. No. 3,653,932 discloses an ink containing a dialkyl sebacate. U.S. Pat. No. 4,390,369 and Japanese Patent Application Laid-open No. 58-108271 disclose an ink containing a natural wax. Japanese Patent Application Laid-open No. 59-22973 discloses an ink containing a stearic acid. Japanese Patent Application Laid-open No. 61-83268 discloses an ink containing an acid or alcohol having 20 to 24 carbon atoms and also containing a ketone having a relatively higher melting point than these. Japanese Patent Application Laid-open No. 62-48774 discloses an ink containing a thermosetting resin having a high hydroxyl value, a solid organic solvent having a melting point lower than 150.degree. C. and a small quantity of a dye substance. Japanese Patent Application Laid-open No. 62-112627 discloses an ink comprised of a colorant, a first solvent which is solid at room temperature and capable of liquefying upon heating to a temperature higher than the room temperature and a second solvent capable of dissolving the first solvent, being liquid at room temperature and being highly volatile. Japanese Patent Application Laid-open No. 62-295973 discloses an ink containing a synthetic wax having a polar group and a dye soluble in the wax.
These conventional hot-melt inks are set in color ink-jet recording apparatus, where the ink is liquefied by heating, and is ejected from an ejection mechanism while being kept liquid, to print images on a printing medium. However, color ink-jet recording carried out using conventional color hot-melt inks has a low color-forming performance and has not been able to form color images having a good color reproduction.